1. Firstly, you need Orpheu. You have just to unzip the content of orpheu_base.zip in ./amxmodx/ ;
2. Then unzip the content of the provided archive here in ./amxmodx/ ;
3. Install the plugin*, restart and it's ready.
* You need to compile locally the plugin since it uses third party includes from Orpheu.
I did everything here but I don't know where to put the .sma so I can compile it. I tried in the scripting folder and the amx folder itself.